class Point {
	int x,y;
	void setXY(int m,int n) {
	   x = m;
	   y = n;
	}
}
public class Example4_4 {
	public static void main (String args[]) {
	  Point p1,p2;
	  p1 = new Point();
	  p2 = new Point();
	  System.out.println("p1的引用："+p1);
	  System.out.println("p2的引用："+p2);
	  p1.setXY(1111,2222);
	  p2.setXY(-100,-200);
	  System.out.println("p1的x,y坐标:"+p1.x+p1.y);
	  System.out.println("p2的x,y坐标:"+p2.x+p2.y);
	  p1 = p2;
	  System.out.println("将p2的引用赋给p1后:");
	  System.out.println("p1的引用："+p1);
	  System.out.println("p2的引用："+p2);
	  System.out.println("p1的x,y坐标:"+p1.x+p1.y);
	  System.out.println("p2的x,y坐标:"+p2.x+p2.y);
	}
}